# CVE-2021-36194: Memory corruption in Fortinet FortiWeb

> Authenticated attackers can achieve arbitrary code execution via stack-based buffer overflows in FortiWeb API controllers.

- **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:U/RC:C`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 9 Dec 2021
- **Updated:** 25 Oct 2024
- **Also known as:** GHSA-x4wq-ph23-36hw

## What is CVE-2021-36194?

CVE-2021-36194 is a high-severity memory corruption vulnerability in Fortinet Fortiweb, published on 9 Dec 2021. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Multiple stack-based buffer overflows in the API controllers of FortiWeb 6.4.1, 6.4.0, and 6.3.0 through 6.3.15 may allow an authenticated attacker to achieve arbitrary code execution via specially crafted requests.

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2021-36194?

It affects 1 product.


Products: Fortinet Fortiweb.

## How do I fix CVE-2021-36194?

No fix has been published for CVE-2021-36194 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-36194 being exploited?

There is no known exploitation of CVE-2021-36194 in the wild and no public exploit code.

## Other vulnerabilities in Fortinet Fortiweb

- [CVE-2025-25257](https://insights.sbomify.com/CVE-2025-25257/): Fortinet FortiWeb SQL Injection (critical 9.6, exploited in the wild)
- [CVE-2025-64446](https://insights.sbomify.com/CVE-2025-64446/): Fortinet FortiWeb Path Traversal (critical 9.4, exploited in the wild)
- [CVE-2025-58034](https://insights.sbomify.com/CVE-2025-58034/): Fortinet FortiWeb OS Command Injection (medium 6.7, exploited in the wild)
- [CVE-2020-29015](https://insights.sbomify.com/CVE-2020-29015/): SQL injection in Fortinet FortiWeb (critical 9.8)
- [CVE-2020-29016](https://insights.sbomify.com/CVE-2020-29016/): Memory corruption in Fortinet FortiWeb (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-36194 and fix it if it is affected.

What it is: CVE-2021-36194 is a high-severity memory corruption vulnerability in Fortinet Fortiweb, published on 9 Dec 2021. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-36194 in the wild and no public exploit code.

Affected product: Fortinet Fortiweb. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2021-36194/ (Markdown: https://insights.sbomify.com/CVE-2021-36194/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-36194
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-36194
- OSV: https://osv.dev/vulnerability/CVE-2021-36194

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-36194/
Summaries are generated and may contain mistakes; the official description above is the record.